Priest etal
tower top for logging spar



Se t. 20, 1966 R. G. PRIEST ETAL 3,

TOWER TOP FOR LOGGING SPAR Filed Oct. 28, 1963 Q a Sheets-Sheet 1 DEANK. McCURDY REID G. PRIEST INVENTORS BYTMMM ATTORNEYS Sept. 20, 1966 R.G. PRIEST ETAL TOWER TOP FOR LOGGING SPAR -2 Sheetsheet 2 Filed Oct. 28,1963 DEAN K.MCGURDY REID G. PRIEST INVENTORS ATTORNFYS United StatesPatent 3,273,722 TOWER TOP FOR LOGGING SPAR Reid G. Priest and Dean K.McCurdy, Port Angeles,

Wash., assignors, by direct and mesne assignments, to

Hyster Company, Portland, Oreg., a corporation of Nevada Filed Oct. 28,1963, Ser. No. 319,219 2 Claims. (Cl. 212-70) This invention relates tonew and useful improvements in logging equipment and more particularlyto new improvements in a tower top and fair-lead assembly situated atthe top of a mobile and portable spar used in logging operations.

In logging operations as previously carried out in the lumbering areasof the United States, suitable spar trees would be selected and riggedfor logging. In recent years logging has gone further into the hills andit has become increasingly more difiicult to find suitable trees to beused as spa-rs. Furthermore, operating costs have increased manyfold andthis economic fact, along with the lack of spar trees, has given rise tothe use of portable prefabricated spar towers that are transportedhorizontally and partially dismantled from location to location bytruck, tractor or sled and are then erected and guyed at the selectedlocation.

One of the problems which accompanies the use of new portable type spartowers is that of an effective and acceptable tower top and fair-leadassembly. One of the factors which has operated to make currently knowntower tops unacceptable is that there is no provision for avoidingtangling and wearing of the main and haul back cables which are reevedthrough the tower top. Such lack of separation causes rapid wear and alltoo frequent replacement of the cables. Additionally, present devicesrequire large bearing structures because of their design which placesthe load carrying and thrust support elements too far below the blocks.Furthermore, design deficiencies dictate that they be made heavier inorder to compensate for design and also that the bearings be large inorder to contain the necessary strength.

The tower top and fair lead assembly of this invention seeks to overcomethe disadvantages of heretofore known devices by departing fromconventional design standards. In efiect, the tower top and fair leadassembly of this invention provides for reeving the main and haul backcables over free turning sheaves or fair leads which have their verticalaxes of rotation non-concentric or noncoincident. Furthermore, the heavybearing structures which are necessary in presently known devices aredone away with since the moments created at the tower top by the forcesexerted on the cables are reduced. In elfect, the tower top sheavemounting structure is rigid to a point above the main block and to apoint just below the horizontal shaft of the haul back sheave.

Accordingly, it is a feature of this invention to provide a tower topwhich because of the spaced axes of the main and haul back block pivotseliminates the rubbing and twisting and consequent wearing of the twocables since they are maintained or threaded through the assembly indistinctly separate channels.

Another feature of this invention is to supply a tower top assemblywhich reduces the moments or thrust created by the cables and thebearings thus enabling the 3,273,722 Patented Sept. 20, 1966 design toemploy smaller bearings and to be lighter in structure;

Still another feature of this invention is to furnish a tower topassembly which may be attached to a tower of any height.

Still another feature of this invention is to provide a tower topassembly which permits the angle of cant of the tower top assembly to bevaried according to the nature of the engine and winch equipment usedfor the yarding operation.

A further feature of this invention is to furnish a tower top assemblywhich is simple in design, rugged in construction and economical toproduce.

These, together with other features and advantages which will becomesubsequently apparent, reside in the details of the construction andoperation as more fully hereinafter described and claimed. Referencewill be had to the accompanying drawings, forming a part here of,wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is an environmental illustration, essentially diagrammatic,showing a portable type logging tower base and spar and showing wherethe tower top and fair lead assembly of this invention is included inthe operation;

FIGURE 2 is a side elevational view of this structure showing in greaterdetail the general arrangement of the parts and elements containedtherein; and

FIGURE 3 is a section view taken through the horizontal center of thedevice to. more clearly illustrate the details of its construction.

Referring now to the drawings, and especially FIG- URE 1, it will beseen that the environment in which this invention is used is comprisedgenerally of a mobile power base unit 10. The tower base is shown in thedrawings to be truck mounted merely for the purposes of illustration.Numerous other methods for transporting the tower base unit are knownand will readily occur to persons skilled in the art. Truck 12 and itstower base extension carry yarder engine 14, haul back winch 16, mainwinch 18, and the tower hoisting frame apparatus 20. The tower itselfgenerally shown by number 22 has guyline drums 24, tower base supportingmeans 26, and the tower top and fair lead assembly generally shown bythe number 30.

As can be seen from FIGURES 2 and 3 the tower top has the haul backsheave 32 and the main cable sheave 34. The main sheave 34 has reevedthereover the main cable 36 while the haul back sheave 32 has reevedthereover the haul back cable 38. The sheaves are supported at the topof the tower 22 by a supporting housing generally designated by thenumber 40. Housing 40 is a single piece casting which is either weldedor bolted at an angle as at 42 to the tower top. Housing 40 is such asto cover the whole of the tower top and to extend outwardly rearwardlythereof. The angle line 42 at which the housing is secured to the toweris determined primarily by the nature of the engine employed to drivethe haul back and main cable winches. The yarder engine and winchescould be close to the base of the tower in which case the angle from thehorizontal along the line 42 would be slight. On the other hand, if thepower unit is located somewhat away from the tower base then the anglewould become slightly greater from the horizontal.

Housing 40 has a base section 44 extending from the ,the shaft 92 of thesheave.

front of the tower as at 23 and extending out from the rear line 25 ofsaid tower to point 46 forming the lower and rear most point of thehousing 40. The rear of housing 40 is a generally upstanding longtapering, essentially irusto-conical, tubular haul back support section48 which is open at the bottom thereof. For purposes Oif comparison itshould be understood that the dimension from the line 42 at the base ofhousing 40 to the top of the tubular haul back support section 48 isapproximately 44 inches. The upper portion 50 of the housing 40 extendsoutwardly generally parallel to the base portion 44 for approximatelyhalf the distance as said base section 44.

An opening 76 is provided below and coaxially aligned with bearingsupport portions 74. It will be appreciated that the upper section 50 ofthe tower top housing 40 is provided with another opening 72 to permit adetachable or removable generally round bearing cage 78 to be droppedtherein. Bearing cage 78 has upper support flanges 80 which permit thecage to be set into opening 72 in a position for quick attachment to themain housing 40. Bearing cage 78 is removable because of the manner inwhich the main block 80 is attached to the main housing. Note that agenerally tubular main block support portion 82 has tapering ends 84 and86. Bearing cage 78 has the depending cylindrical bearing supportportion 81 for receiving the upper main thrust bearing 88. In likemanner the bearing support portion 74 at the base supports lower mainthrust bearing 90. Thus, the upper end of the upper tapering end 84 ofthe main block 80 is received into the bearing support section of thehearing cage. In like manner the lower end of the lower tapered end 86is received into the thrust bearing 90 at the base of the main housing.

It will be seen from the above description that main block 83 which hasshaft 92 for the sheave 34 pivots about its own generally vertical axisin an arc in excess of 200 degrees. Obviously it would be quite possiblefor the haul back block and sheave to rotate a full 360 degrees. It willbe readily appreciated that the main housing 40 can be cast as a singleunit with the bearing cage 78 and the main block support tube 82 alsoeach formed separately. Thus, when the elements are ready to beassembled, the main block can be first inserted at its lower end andthen the bearing cage 78 dropped in on the upper end and bolted inplace. It will be appreciated that the stem 62 of the haul back block 64has support flanges 94 for determining the depth to which it is allowedto be received into the main support section 48. Since the stem 62 isfreely pivotable a holding means 96 is attached to the upper part 50 ofthe main housing 40 to restrain the haul back block from any axialmovement or from being accidentally flipped out of its bearingstructure.

Because conventional tower tops have pivoted both the main and haul backsheaves or blocks on the same axis it has been necessary to run the mainand haul back cables close together thus causing rubbing and twistingand consequent rapid wear. The unique tower top of this inventionpermits :the haul back block to be supported quite near its sheave axis.In other words, the main housing 40 of this tower top acts as a rigidextension of the tower and brings rigid support up to the sheave axis70. In like manner the main sheave has rigid structure both above andbelow in which to be mounted. In this manner bearings are permitted tobe smaller than they would be in an instance where all of the thrust hadto be taken below Since the moments created by the stresses on .the haulback and main sheaves have been reduced by raising rigid supportingstructure higher with relation to the axes of rotation of the sheaves,the bearing structure for the haul 'back block can also be lighter. Thetotal result is a light and stronger and more dependable tower top.

It will be noted from the drawings (that the tower top 30 is providedwith a series of eyes or holes through which the U-sha'ped guy lineshackles '21 are looped. Each 4 shackle has attached thereto the blockside plates 23 which carry a sheave 25 therebetween- The shackles aresecured to the block side plates by shackle bolts 29. Such guylinestructures are conventional in the art and are only described in orderto complete a picture of the environment in which the invention is used.

It will also be noted, particularly by reference to FIG. 3 that thetower top may be modified some-what and still retain its advantages.Thus, the main block and its housmg may be pivotally secured by a stemjournalled in the upper end of the spar. In this way the main sheave 34will have its tubular block housing closed as along line '85, thusdispensing with the upper bearing structure lfor said main blockhousing. However, additional rigid structure 73 will have to be providedon the base portion of the lower rtop housing, together with addedbearings 75 and stem 77 at the lower end of the tubular main blockhousing. In this way, the spirit and principle of the preferred form ofthe invention is retained.

The foregoing is considered as illustrative only of the principle ofthis invention. Since numerous modifications and changes will readilyoccur to those skilled in the art, it is not desired to limit theinvention to the exact construction shown and described.

What is claimed is:

1. A tower top and rfairleader assembly for a generally verticallydisposed portable logging spar, comprising:

(a) a main tower top housing mounted on the top of said spar including afirst tubular section being open at both its upper and lower ends;

(b) a base section extending generally outwardly at a right angle .tosaid first tubular section and having a cable opening therein;

(c) a top support section extending generally outwardly at a right angleto said first tubular section and having a bearing cage means detaohablymounted therein generally coaxially with said cable opening in said baseportion;

(d) a first block means with tubular stem means pivotally mounted andreceived within the upper portion of said first tubular section;

(e) a second generally tubular block support section pivotally supportedby said bearing cageand by bearing means concentrically disposed aroundsaid cable opening for pivoting in non-concentric but generally parallelrelation to said first block means; and

(i) said housing with said first and second tubular block sections beingmounted at an angle on said vertically disposed spar so that said blocksections pivot at an angle to said spar, the lower open end O f saidfirst tubular section located generally outside the vertical plane ofthe walls of said spar, said angular mounting of said tubular sectionspermitting cables to pass downwardly from said housing and the topmostportion of said spar outside said spar.

2. A tower top and 'fairleader assembly for a generally verticallydisposed portable logging spar, comprising:

(a) a main tower top housing mounted on the top of said spar including afirst tubular section being open at both its upper and lower ends;

(b) a base section extending generally outwardly at a right angle :tosaid first tubular section and having a cable opening therein;

(0) a top support section extending generally outwardly at a right angleto said first tubular section and having a bearing cage means detachablymounted therein generally coaxially with said cable opening in said baseportion;

(d) a first block means with tubular stem means pivotally mounted andreceived within the upper portion of said first tubular section;

(e) a second generally tubular block support section p'ivotallysupported by said bearing cage and by bearing means concentricallydisposed around said cable opening for pivoting in non-concentric butgeneral- 1y parallel relation to said first block means, said bearingcage being generally on a level with said stem means of said first blockmeans; and

(If) said housing with said tubular sections being mounted at an angleon said vertically disposed spar with the lower open end of said firsttubular section located generally outside the vertical plane of theWalls of said spar, and said housing having all bear- References Citedby the Examiner UNITED STATES PATENTS Burton 2127 B-urton 2127 McIntyre212-7 McIntyre 21270 Slagle 254-1391 Troyer.

ing structure located generally above its mounting on 10 EVON PrimaryExaminer SAMUIEL F. COLEMAN, Examiner.

A. LEVINE, Assistant Examiner.

said spar.

1. A TOWER TOP AND FAIRLEADER ASSEMBLY FOR A GENERALLY VERTICALLYDISPOSED PORTABLE LOGGING SPAR, COMPRISING: (A) A MAIN TOWER TOP HOUSINGMOUNTED ON THE TOP OF SAID SPAR INCLUDING A FIRST TUBULAR SECTION BEINGOPEN AT BOTH ITS UPPER AND LOWER ENDS; (B) A BASE SECTION EXTENDINGGENERALLY OUTWARDLY AT A RIGHT ANGLE TO SAID FIRST TUBULAR SECTION ANDHAVING A CABLE OPENING THEREIN; (C) A TOP SUPPORT SECTION EXTENDINGGENERALLY OUTWARDLY AT A RIGHT ANGLE TO SAID FIRST TUBULAR SECTION ANDHAVING A BEARING CAGE MEANS DETACHABLY MOUNTED THEREIN GENERALLYCOAXIALLY WITH SAID CABLE OPENING IN SAID BASE PORTION; (D) A FIRSTBLOCK MEANS WITH TUBULAR MEANS PIVOTALLY MOUNTED AND RECEIVED WITHIN THEUPPER PORTION OF SAID FIRST TUBULAR SECTION; (E) A SECOND GENERALLYTUBULAR BLOCK SUPPORT SECTION PIVOTALLY SUPPORTED BY SAID BEARING CAGEAND BY BEARING MEANS CONCENTRICALLY DISPOSED AROUND SAID CABLE OPENINGFOR PIVOTING IN NON-CONCENTRIC BUT GENERALLY PARALLEL RELATION TO SAIDFIRST BLOCK MEANS; AND (F) SAID HOUSING WITH SAID FIRST AND SECONDTUBULAR BLOCK SECTIONS BEING MOUTNED AT AN ANGLE ON SAID VERTICALLYDISPOSED SPAR SO THAT SAID BLOCK SECTIONS PIVOT AT AN ANGLE TO SAIDSPAR, THE LOWER OPEN END OF SAID FIRST TUBULAR SECTION LOCATED GENERALLYOUTSIDE THE VERTICAL PLANE OF THE WALLS OF SAID SPAR, SAID ANGULARMOUNTING OF SAID TUBULAR SECTIONS PERMITTING CABLES TO PASS DOWNWARDLYFROM SAID HOUSING AND THE TOPMOST PORTION OF SAID SPAR OUTSIDE SAIDSPAR.